Abstract:

In this field experiment，seven-year-old pear trees（Pyrus pyrifolia‘Hwangkumbae’）
were treated by 15N-tracer to research the effects of fertilization depth（0，20 and 40 cm）on nitrogen
absorption，distribution and utilization of different pear trees organs，residual and loss in the soil. The
results indicate that the 15N derived from fertilizer （Ndff）was the highest in the fruit at fruit maturity stage，
and the Ndff in other organs of 20 cm treatment is significant higher than that of other treatments. The 15N
distribution ratio of each treatment is highest in storage organs and lowest in vegetative organs. The N
utilization ration of 20 cm depth treatment is highest （26.23%），and that of 40 cm depth treatment is lowest
（15.65）；the N loss ration of 40 cm depth treatment is the highest（54.21%），and that of 20 cm depth
treatment is lowest；the N residual ration during 0–80 cm depth soil of 40 cm depth treatment is the highest （31.73%），and that of 0 cm depth treatment is lowest. Thus，the 20 cm depth treatment can enhance the
absorption and ability to transfer N to organs of pear trees，and reduce the nitrogen loss and residual in the
soil in this study.

Key words: pear, fertilization depth, Ndff, distribution ratio of 15N, utilization ratio of N